Infill housing" is one of those phrases that planning geeks love, shorthand for any residential development that doesn't include cul de sacs on land where crops were farmed last year.

But all it takes to grasp the inadequacy of the term is to visit two recent additions to the San Francisco landscape. One is an eight-story stack of 14 condominiums slid into a narrow lot across from the Giants' ballpark. The other fills two blocks along a streetcar line in a sleepy commercial district, with a grocery store as well as 173 apartments."